Certain well known fluid meters, including water meters, utilize a nutating disc metering element to measure the flow of fluid through a metering chamber. The fluid passing through the metering chamber imparts a nutating (wobbly) motion to the disc which is converted to a rotary motion or other motion to actuate a counter or register for the meter. The pressure and velocity of fluid entering the metering chamber provides considerable force on the nutating disc, and this force is transmitted to the measuring chamber housing where contact between the two elements occurs. The forces imparted by the fluid must be counteracted to insure the accuracy and the proper functioning of the meter.
For many years, a thrust roller mechanism has been used to counter such forces. This mechanism is disclosed in Miller, U.S. Pat. No. 1,957,661, which was assigned to the assignee of this invention, and a good depiction is illustrated in Thomson, U.S. Pat. No. 10,022, FIG. 17. A thrust roller is attached to the disc diametrically opposite the inlet of the measuring chamber, where the thrust roller rolls up and down in a slot in the meter casing. Such slots utilize various types of bearing inserts which are placed in proximity to the roller to minimize wear and reduce friction, which would impede proper nutation of the disc. These inserts are replaceable and are of common use in nutating disc type metering devices which are used by many municipalities for metering water used by subscribers. Such thrust rollers and inserts tend to wear over time and present certain problems in manufacture, assembly and servicing of the meter.